The invention is based on an apparatus for injecting a fuel-air mixture for multi-cylinder internal combustion engines.
In injection apparatuses of this kind, in contrast to previously conventional fuel injection devices, it is not pure fuel but rather a mixture of fuel and a supporting air flow diverted from the intake line of the engine that is brought to the injection points of the engine. The fuel-air mixture is carried to the injection points of the various cylinders of the engine via the injection lines connected to the various distributor bores. The injection point may be the intake tube, leading to each engine cylinder, of the intake line or the inlet valve of the cylinder. Mixing the fuel prior to the actual injection into the cylinder results first in better preparation of the fuel and hence more favorable combustion in the engine; second, it offers the opportunity to supply a plurality of engine cylinders while having exact metering, using only a single fuel injection valve.
In a known apparatus of the type referred to at the outset above (German Patent Disclosure Document 37 10 127 A1), the valve member is embodied on a sheath that is axially displaceably guided on a shaft and is connected to the electromagnet. The shaft has a flange on one end that rests on the distributor and has fuel metering bores that ar coaxial to the distributor bores; on the top of the flange, remote from the distributor, these bores are closed by the valve member, which is pressed onto the flange by a valve closing spring. Upstream of the flange as viewed in the fuel flow direction, there is a valve chamber receiving the valve closing spring; this chamber communicates on the one hand with the fuel inflow, via the hollow-cylindrical annular conduit, which is coaxial with the shaft, between the sheath and the electromagnet and on the other with the fuel return, via a pressure regulating valve.